Soundproof window construction for aircraft cabins



S. J. ZAND Feb. 6, 19.40.

SOUNDPROOF WINDOW CONSTRUCTION FOR AIRCRAFT CABINS Filed July '7, 1936 INVENTOR STEPHEN J. ZAND ATTORNEY.

- pane windows.

Patented Feb. 6, 1940 UNITED STATES PATENT OFFICE SOUNDPROOF WINDOW CONSTRUCTION FOB AIRCRAFT CABINS Application July 7, 1936, Serial No. 89,315

2 Claim.

This invention relates to window construction for cabins of aircraft designed to fly at high altitudes. At altitudes above 10,000 to 15,000 feet, the air is extremely cold, with the result that ordinary windows will frost up so that visibility is partially or totally obscured. In addition, too much cold would enter the cabin through the usual single pane. I propose, therefore, to employ double window panes for such aircraft, preferably spaced sufficiently so as to act to keep sound out of the cabin as well as to keep out the cold and prevent frosting.

Referring to the drawing illustrating one form my invention may assume:

Fig. 1 is a vertical section through a portion of the window frame and two spaced panes held.

therein.

Fig. 2 is a diagrammatic interior view of an airplane cabin, showing the ventilating means I provide for the space between the window panes.

As shown in Fig. 1, I preferably employ two spaced panes l and 2, preferably placed at more distance apart than is usual in ordinary double I find that if the distance between the panes is on the order of less than two inches, there is a sufficient coupling between the panes to transmit practically as much sound as if a single window were used. By spacing the panes at least two inches or more, I provide a much better barrier to the entrance of sound. Preferably both panes are of safety glass and the pane exposed to the major diiference in pressure on the two sides is made the thicker. As shown in Fig. 1, the outer pane is the thicker, thus being adapted to a condition where the space between the panes is sealed or connected to the interior of the cabin. Both panes are mounted in a rubber channel piece which, in turn, is either molded or vulcanized to the metal frame 4. Preferably said rubber piece is constructed on the principle covered in my prior.

Patent 1,991,832, dated February 19, 1935, for soundproof window construction, so as to prevent the transmission of vibrations to the window. Inside the window I place sound absorbing material 5, such as kapok, rock wool or seapack, which I may cover by some acoustically transparent medium 6, such as a wire screen, ornamental perforated metal, or cloth.

Preferably, I provide a vent pipe I connecting the inside space between the two panes and the outside of the airplane. As shown in Fig. 2, each vent pipe 1! is connected to a longitudinal pipe 8 running along the inner wall of the craft, which pipes join at 9 and are connected to the outside of the airplane as through Venturi tube 6 I also may provide a means for drying the air between the panes to further prevent frosting. To this end, I have shown pipes 8 connected at their opposite ends to a canister H which may contain a hygroscopic material, such as calcium 1o chloride or silica gel, to absorb any moisture of the air entering between the panes. By placing the canister inside of the passengers compartment, a continuous flow of dry air will be produced, since the passengers compartment at 15 high altitude is maintained under pressure above that of the surrounding. atmosphere. The flow of air through the pipes may be restricted, as desired, so that the pressure between the panes may be nearer cabin pressure than atmospheric 2;;

pressure, if desired.

Between the outer wall l2 and inner wall i3 of the cabin I have shown sheets of sound absorbing material It suitably woven back and forth so as to touch said walls at spaced points and damp the vibrations thereof without trans- 25 mitting the vibrations. As many changes could be made in the abov construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is 30 intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in alimiting sense.

Having described my invention, what I claim 35 and desire to secure by Letters Patent is:

1. In a window construction for soundproofed cabins for aircraft, a pair of spaced window panes for each window, a slotted rubber window frame around each pane, and vibration and sound absorbing material around said frames between the inner faces of the rubber frames for the panes to absorb sound vibrations in the air between said panes and to prevent sound vibrations transmitted from one pane to the other.

2. In a high altitude aircraft cabin, a pair of window panes spaced apart a sufllcient distance to avoid acoustical coupling between said panes, a slotted rubber mounting for securing the edges of said panes to the window frames of the craft, and sound absorbingmaterial around the inside border of said panes and between the rubber forming the inner sides of the slots.

STEPHEN J. mm). 

